Patent GB-1111882-A (GB)
Title: Electric sign devices
IPC: G09G3/00
Filed: 1965-06-03
Abstract: 1,111,882. Electric sign devices. MATSUSHITA ELECTRONICS CORPORATION. 3 June, 1965 [17 June, 1964; 10 Aug., 1964], No. 23824/65. Heading H4F. The invention relates to an electric sign device comprising a sign board having a rectangular screen formed of a plurality of incandescent lamps arranged in a matrix and an electric signal generator for reproducing on the screen a moving image having brightness and darkness corresponding to an original picture provided on a continuously moving tape. As shown, Fig. 1, the signal generator comprises a single line of photoconductive cells r 1 -r n  on a base B of insulating material, the tape T being arranged to move continuously between the photoconductive cells and a light source L. The original picture C is drawn with opaque paint on the tape surface when the tape is transparent or if the tape is of high reflectibility the picture C is arranged to be of low reflectibility. With an opaque picture C the resistance of the photoconductive cells increases abruptly when the picture moves between the cells and the light source. The lamps of the screen are arranged in columns each of the lamps in the first column being directly connected to a corresponding photo-conductive cell. Thus. for example, if the resistance of the second photoconductive cell r 2  abruptly increases a pulse is produced at the output of waveform shaping circuit F, Fig. 2, e.g. a differentiating circuit. which drives transistor T 21  of a bi-stable multivibrator to its " cut-off " state and transistor T<SP>1</SP> 21  to its " on " state, closing switches S 21  and S<SP>1</SP> 21  which lights lamp l 12  positioned in column 1, row 2 (corresponding to cell r 2 , i.e. the second cell). In the course of the above manner of on-off control of the lamps in the first column, positive pulses are periodically supplied at predetermined time intervals to a terminal P. One positive pulse supplied to the terminal P is transmitted through a diode d 21  and switch S<SP>1</SP> 21  and drives transistor T 22  of a bi-stable multivibrator to its " cut-off " state and transistor T<SP>1</SP> 22  to its " on " state which lights lamp l 22  positioned in column 2, row 2. When a succeeding positive pulse is supplied to the terminal P lamp l 23  disposed in column 3, row 2 is energized and thus the lamps disposed in row 2 of the sign board are successively subjected to sequence control in the direction of row 2 and the time interval of sequence control is in synchronism with the time intervals of generation of the pulses applied to the terminal P. While this on-off control in the direction of the line proceeds, new electric signals corresponding to the advancing original picture are successively generated by the photoconductive cell r 2  and these signals directly (for the first column) and indirectly (for the columns after and including the second column) effect the on-off control of lamps l 21 , l 22 , l 23  . . . one after another. Each of the photoconductive cells r 1 , r 2  . . . r n  is provided with a circuit as shown in Fig. 2. Positive-negative inversion of the bright-dark contrast image may be effected by connecting transistor T<SP>1</SP> 21  to the output of the wave-form shaping circuit F instead of transistor T 21 . The Specification includes a detailed description of a modified form of the circuit network, Fig. 3, not shown. The movement of original picture C is strictly synchronized with the generation of pulses applied to the terminal P by means of a multiplicity of black dots (E, Fig. 5, not shown), printed on the lower edge of the tape. The original picture C is arranged to correspond with a group of black dots, these dots being used to generate pulses for application to the terminal P. To impart colour to an image to be displayed on the sign board each lamp is replaced by a set of three lamps emitting different colours, e.g. red, green and blue, and two additional photoconductive cells which control the operation of two relay switches are provided for each row, Fig. 6, not shown, the conductive states of the two photoconductive cells being determined by means of a colour selection track on the tape. With both cells non-conducting the image is coloured red, with one cell conducting the image is coloured blue and with both cells conducting the image is coloured green.